Reworking some stuff so that functions only allow expressions to be

return values with either an explicit "return" statement or if they're
the only line in the function, and the line is an expression.

6 files changed, 69 insertions, 70 deletions

diff --git a/lib/collections.nom b/lib/collections.nom
index b97c164..9939c9b 100644
--- a/lib/collections.nom
+++ b/lib/collections.nom
@@ -51,7 +51,7 @@ compile [%list ->* %indices] to:
     %ret = "\(%list as lua)"
     for %index in (%indices's "value"):
         %ret join= "[\(%index as lua)]"
-    "\%ret"
+    return "\%ret"
 
 # Assignment
 compile [..]
@@ -76,35 +76,35 @@ rule [flatten %lists] =:
     for %list in %lists:
         for %item in %list:
             add %item to %flat
-    %flat
+    return %flat
 
 rule [dict %items] =:
     %dict = []
     for %pair in %items:
         %dict -> (%pair -> 1) = (%pair -> 2)
-    %dict
+    return %dict
 
 rule [entries in %dict] =:
     %entries = []
     for %k = %v in %dict:
         add {key=%k, value=%v} to %entries
-    %entries
+    return %entries
 
 rule [keys in %dict] =:
     %keys = []
     for %k = %v in %dict: add %k to %keys
-    %keys
+    return %keys
 
 rule [values in %dict] =:
     %values = []
     for %k = %v in %dict: add %v to %values
-    %values
+    return %values
 
 # List Comprehension
 compile [%expression for %item in %iterable] to:
     assert ((%item's "type") == "Var") ".."
         List comprehension has the wrong type for the loop variable. Expected Var, but got: \(%item's "type")
-    ".."
+    return ".."
         (function(nomsu, vars);
             local comprehension = {};
             for i,item in ipairs(\(%iterable as lua)) do;
@@ -120,7 +120,7 @@ compile [%expression for %key = %value in %iterable] to:
         List comprehension has the wrong type for the key loop variable. Expected Var, but got: \(%key's "type")
     assert ((%value's "type") == "Var") ".."
         List comprehension has the wrong type for the value loop variable. Expected Var, but got: \(%value's "type")
-    ".."
+    return ".."
         (function(nomsu, vars);
             local comprehension = {};
             for key,value in pairs(\(%iterable as lua)) do;
@@ -133,11 +133,11 @@ compile [%expression for %key = %value in %iterable] to:
 rule [%items sorted] =:
     %copy = (% for all %items)
     sort %copy
-    %copy
+    return %copy
 rule [%items sorted by %key] =:
     %copy = (% for all %items)
     sort %copy by %key
-    %copy
+    return %copy
 rule [unique %items] =:
     keys in (dict ([%,yes] for all %items))
 
@@ -165,7 +165,7 @@ rule [chain %dict to %fallback] =:
 compile [%key = %value for %item in %iterable] to:
     assert ((%item's "type") == "Var") ".."
         Dict comprehension has the wrong type for the loop variable. Expected Var, but got: \(%item's "type")
-    ".."
+    return ".."
         (function(nomsu, vars);
             local comprehension = {};
             for i,value in ipairs(\(%iterable as lua)) do;
@@ -181,7 +181,7 @@ compile [%key = %value for %src_key = %src_value in %iterable] to:
         Dict comprehension has the wrong type for the key loop variable. Expected Var, but got: \(%src_key's "type")
     assert ((%src_value's "type") == "Var") ".."
         Dict comprehension has the wrong type for the value loop variable. Expected Var, but got: \(%src_value's "type")
-    ".."
+    return ".."
         (function(nomsu, vars);
             local comprehension = {};
             for key,value in pairs(\(%iterable as lua)) do;
diff --git a/lib/control_flow.nom b/lib/control_flow.nom
index 72a2ad1..33f72ab 100644
--- a/lib/control_flow.nom
+++ b/lib/control_flow.nom
@@ -210,7 +210,7 @@ compile [when %body] to code:
 
     if (%result != ""):
         %result join= "\nend"
-    %result
+    return %result
 
 # Switch statement
 compile [when %branch_value == ? %body] to code:
@@ -259,7 +259,7 @@ compile [when %branch_value == ? %body] to code:
             ..\%result
             end
             end --when == ?
-    %result
+    return %result
 
 # Try/except
 compile [..]
diff --git a/lib/operators.nom b/lib/operators.nom
index 8ea7aad..59a9ad2 100644
--- a/lib/operators.nom
+++ b/lib/operators.nom
@@ -12,8 +12,8 @@ compile [phi, PHI, golden ratio] to: "((1+math.sqrt(5))/2)"
 compile [nop, pass] to code: ""
 
 # Ternary operator
-#.. Note: this uses a function instead of (condition and if_expr or else_expr)
-    because that breaks if %if_expr is falsey.
+#.. Note: this uses a function instead of "(condition and if_expr or else_expr)"
+    because that breaks if %if_expr is falsey, e.g. "x < 5 and false or 99"
 compile [..]
     %when_true_expr if %condition else %when_false_expr
     %when_true_expr if %condition otherwise %when_false_expr
@@ -27,6 +27,17 @@ compile [..]
             return \(%when_false_expr as lua);
         end
     end)(nomsu, vars)
+parse [..]
+    %true if %x == %y else %false, %true if %x == %y otherwise %false
+    %false unless %x == %y else %true, %false unless %x == %y otherwise %true
+..as:
+    %true if (%x == %y) else %false
+
+parse [..]
+    %true if %x != %y else %false, %true if %x != %y otherwise %false
+    %false unless %x != %y else %true, %false unless %x != %y otherwise %true
+..as:
+    %true if (%x != %y) else %false
 
 # Indexing:
 compile [%obj'%key, %obj's %key, %obj -> %key] to: "(\(%obj as lua))[\(%key as lua)]"
diff --git a/lib/utils2.nom b/lib/utils2.nom
index 89a0767..2fa29f7 100644
--- a/lib/utils2.nom
+++ b/lib/utils2.nom
@@ -6,16 +6,12 @@ require "lib/collections.nom"
 
 
 compile [say %str] to:
-    if ((%str's "type") == "String"):
-        "nomsu:writeln(\(%str as lua))"
-    ..else:
-        "nomsu:writeln(nomsu:stringify(\(%str as lua)))"
+    "nomsu:writeln(\(%str as lua))" if ((%str's "type") == "String")
+    ..else "nomsu:writeln(nomsu:stringify(\(%str as lua)))"
 
 compile [do %action] to code:
-    if ((%action's "type") == "Thunk"):
-        %action as lua statements
-    ..else:
-        "(\(%action as lua))(nomsu, vars);"
+    (%action as lua statements) if ((%action's "type") == "Thunk")
+    ..else "(\(%action as lua))(nomsu, vars);"
 
 # With statement
 compile [with %assignments %action] to code:
@@ -33,7 +29,7 @@ compile [with %assignments %action] to code:
             "local old_value\(%->"i") = \((%->"var") as lua); \((%->"var") as lua) = \((%->"value") as lua);"
             ..for all %data
         ..with glue "\n    "
-    ".."
+    return ".."
         do
             \%setup
             local fell_through = false;
@@ -51,26 +47,17 @@ parse [with %thing = %value %action] as: with [%thing = %value] %action
 
 # Any/all/none
 compile [all of %items, all %items] to:
-    if (%items' "type") == "List":
-        "(\(join ((% as lua) for all (%items' "value")) with glue " and "))"
-    ..else:
-        "nomsu.utils.all(\(%items as lua))"
+    "(\(join ((% as lua) for all (%items' "value")) with glue " and "))"
+    ..if (%items' "type") == "List" else "nomsu.utils.all(\(%items as lua))"
 parse [not all of %items, not all %items] as: not (all of %items)
 compile [any of %items, any %items] to:
-    if (%items' "type") == "List":
-        "(\(join ((% as lua) for all (%items' "value")) with glue " or "))"
-    ..else:
-        "nomsu.utils.any(\(%items as lua))"
+    "(\(join ((% as lua) for all (%items' "value")) with glue " or "))"
+    ..if (%items' "type") == "List" else "nomsu.utils.any(\(%items as lua))"
 parse [none of %items, none %items] as: not (any of %items)
 
-
 compile [sum of %items, sum %items] to:
-    if (%items' "type") == "List":
-        "(\(join ((% as lua) for all (%items' "value")) with glue " + "))"
-    ..else:
-        "nomsu.utils.sum(\(%items as lua))"
+    "(\(join ((% as lua) for all (%items' "value")) with glue " + "))"
+    ..if (%items' "type") == "List" else "nomsu.utils.sum(\(%items as lua))"
 compile [product of %items, product %items] to:
-    if (%items' "type") == "List":
-        "(\(join ((% as lua) for all (%items' "value")) with glue " * "))"
-    ..else:
-        "nomsu.utils.product(\(%items as lua))"
+    "(\(join ((% as lua) for all (%items' "value")) with glue " * "))"
+    ..if (%items' "type") == "List" else "nomsu.utils.product(\(%items as lua))"
diff --git a/nomsu.lua b/nomsu.lua
index 4fd20e8..730ab13 100644
--- a/nomsu.lua
+++ b/nomsu.lua
@@ -528,7 +528,6 @@ do
       self:assert(tree, "Tree failed to compile: " .. tostring(src))
       self:assert(tree.type == "File", "Attempt to run non-file: " .. tostring(tree.type))
       local buffer = { }
-      local return_value = nil
       local _list_0 = tree.value
       for _index_0 = 1, #_list_0 do
         local statement = _list_0[_index_0]
@@ -544,8 +543,7 @@ do
         end
         local code_for_statement = ([[return (function(nomsu, vars)
 %s
-return %s;
-end);]]):format(statements or "", expr or "ret")
+end);]]):format(statements or ("return " .. expr .. ";"))
         if output_file then
           if statements and #statements > 0 then
             output_file:write("lua> \"..\"\n    " .. tostring(self:indent(statements:gsub("\\", "\\\\"))) .. "\n")
@@ -571,9 +569,6 @@ end);]]):format(statements or "", expr or "ret")
         local run_statement = lua_thunk()
         local ret
         ok, ret = pcall(run_statement, self, vars)
-        if expr then
-          return_value = ret
-        end
         if not ok then
           self:errorln(tostring(colored.red("Error occurred in statement:")) .. "\n" .. tostring(colored.yellow(statement.src)))
           self:errorln(debug.traceback())
@@ -583,18 +578,16 @@ end);]]):format(statements or "", expr or "ret")
           insert(buffer, statements)
         end
         if expr then
-          insert(buffer, "ret = " .. tostring(expr) .. ";")
+          insert(buffer, tostring(expr) .. ";")
         end
       end
       if max_operations then
         debug.sethook()
       end
       local lua_code = ([[return (function(nomsu, vars)
-local ret;
 %s
-return ret;
 end);]]):format(concat(buffer, "\n"))
-      return return_value, lua_code, vars
+      return nil, lua_code, vars
     end,
     tree_to_value = function(self, tree, vars, filename)
       local code = "return (function(nomsu, vars)\nreturn " .. tostring(self:tree_to_lua(tree, filename)) .. ";\nend);"
@@ -817,7 +810,7 @@ end);]]):format(concat(buffer, "\n"))
             insert(lua_bits, statement)
           end
           if expr then
-            insert(lua_bits, "ret = " .. tostring(expr) .. ";")
+            insert(lua_bits, tostring(expr) .. ";")
           end
         end
         return nil, concat(lua_bits, "\n")
@@ -829,17 +822,20 @@ end);]]):format(concat(buffer, "\n"))
         for _index_0 = 1, #_list_0 do
           local arg = _list_0[_index_0]
           local expr, statement = self:tree_to_lua(arg, filename)
+          if #tree.value == 1 and expr and not statement then
+            return ([[(function(nomsu, vars)
+    return %s;
+end)]]):format(expr)
+          end
           if statement then
             insert(lua_bits, statement)
           end
           if expr then
-            insert(lua_bits, "ret = " .. tostring(expr) .. ";")
+            insert(lua_bits, tostring(expr) .. ";")
           end
         end
         return ([[(function(nomsu, vars)
-local ret;
 %s
-return ret;
 end)]]):format(concat(lua_bits, "\n"))
       elseif "FunctionCall" == _exp_0 then
         insert(self.compilestack, tree)
@@ -1441,7 +1437,7 @@ if arg then
   colors = require('consolecolors')
   local parser = re.compile([[        args <- {| {:flags: flags? :} ({:input: input :} ";" ("-o;"{:output: output :} ";")?)? (";")? |} !.
         flags <- (({| ({flag} ";")* |}) -> set)
-        flag <- "-c" / "-i" / "-p" / "-O" / "--help" / "-h"
+        flag <- "-c" / "-i" / "-p" / "-O" / "--help" / "-h" / "-v"
         input <- "-" / [^;]+
         output <- "-" / [^;]+
     ]], {
@@ -1454,6 +1450,9 @@ if arg then
     os.exit()
   end
   local c = NomsuCompiler()
+  if args.flags["-v"] then
+    c.debug = true
+  end
   c.skip_precompiled = not args.flags["-O"]
   if args.input then
     if args.flags["-c"] and not args.output then
diff --git a/nomsu.moon b/nomsu.moon
index fd74879..8f77c87 100755
--- a/nomsu.moon
+++ b/nomsu.moon
@@ -342,7 +342,7 @@ class NomsuCompiler
         @assert tree.type == "File", "Attempt to run non-file: #{tree.type}"
 
         buffer = {}
-        return_value = nil
+        -- TODO: handle return statements in a file
         for statement in *tree.value
             if @debug
                 @writeln "#{colored.bright "RUNNING NOMSU:"}\n#{colored.bright colored.yellow statement.src}"
@@ -355,8 +355,7 @@ class NomsuCompiler
             code_for_statement = ([[
 return (function(nomsu, vars)
 %s
-return %s;
-end);]])\format(statements or "", expr or "ret")
+end);]])\format(statements or ("return "..expr..";"))
             if output_file
                 if statements and #statements > 0
                     output_file\write "lua> \"..\"\n    #{@indent statements\gsub("\\","\\\\")}\n"
@@ -374,7 +373,6 @@ end);]])\format(statements or "", expr or "ret")
                 error("Failed to compile generated code:\n#{colored.bright colored.blue colored.onblack code}\n\n#{err}\n\nProduced by statement:\n#{colored.bright colored.yellow statement.src}")
             run_statement = lua_thunk!
             ok,ret = pcall(run_statement, self, vars)
-            if expr then return_value = ret
             if not ok
                 @errorln "#{colored.red "Error occurred in statement:"}\n#{colored.yellow statement.src}"
                 @errorln debug.traceback!
@@ -382,17 +380,15 @@ end);]])\format(statements or "", expr or "ret")
             if statements
                 insert buffer, statements
             if expr
-                insert buffer, "ret = #{expr};"
+                insert buffer, "#{expr};"
         
         if max_operations
             debug.sethook!
         lua_code = ([[
 return (function(nomsu, vars)
-local ret;
 %s
-return ret;
 end);]])\format(concat(buffer, "\n"))
-        return return_value, lua_code, vars
+        return nil, lua_code, vars
     
     tree_to_value: (tree, vars, filename)=>
         code = "return (function(nomsu, vars)\nreturn #{@tree_to_lua(tree, filename)};\nend);"
@@ -546,7 +542,7 @@ end);]])\format(concat(buffer, "\n"))
                 for line in *tree.value
                     expr,statement = @tree_to_lua line, filename
                     if statement then insert lua_bits, statement
-                    if expr then insert lua_bits, "ret = #{expr};"
+                    if expr then insert lua_bits, "#{expr};"
                 return nil, concat(lua_bits, "\n")
             
             when "Nomsu"
@@ -556,13 +552,16 @@ end);]])\format(concat(buffer, "\n"))
                 lua_bits = {}
                 for arg in *tree.value
                     expr,statement = @tree_to_lua arg, filename
+                    if #tree.value == 1 and expr and not statement
+                        return ([[
+(function(nomsu, vars)
+    return %s;
+end)]])\format(expr)
                     if statement then insert lua_bits, statement
-                    if expr then insert lua_bits, "ret = #{expr};"
+                    if expr then insert lua_bits, "#{expr};"
                 return ([[
 (function(nomsu, vars)
-local ret;
 %s
-return ret;
 end)]])\format(concat(lua_bits, "\n"))
 
             when "FunctionCall"
@@ -889,7 +888,7 @@ if arg
     parser = re.compile([[
         args <- {| {:flags: flags? :} ({:input: input :} ";" ("-o;"{:output: output :} ";")?)? (";")? |} !.
         flags <- (({| ({flag} ";")* |}) -> set)
-        flag <- "-c" / "-i" / "-p" / "-O" / "--help" / "-h"
+        flag <- "-c" / "-i" / "-p" / "-O" / "--help" / "-h" / "-v"
         input <- "-" / [^;]+
         output <- "-" / [^;]+
     ]], {:set})
@@ -901,6 +900,9 @@ if arg
 
     c = NomsuCompiler()
 
+    if args.flags["-v"]
+        c.debug = true
+
     c.skip_precompiled = not args.flags["-O"]
     if args.input
         -- Read a file or stdin and output either the printouts or the compiled lua